IMMUNOLOCALIZATION OF SYNEXIN (ANNEXIN-VII) IN ADRENAL CHROMAFFIN GRANULES AND CHROMAFFIN CELLS - EVIDENCE FOR A DYNAMIC ROLE IN THE SECRETORY PROCESS
IMMUNOLOCALIZATION OF SYNEXIN (ANNEXIN-VII) IN ADRENAL CHROMAFFIN GRANULES AND CHROMAFFIN CELLS - EVIDENCE FOR A DYNAMIC ROLE IN THE SECRETORY PROCESS
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DOI：
10.1007/bf00319624
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发表时间：
1992-08-01
影响因子：
3.6
通讯作者：
POLLARD, HB
中科院分区：
文献类型：
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作者：
KUIJPERS, GAJ;LEE, G;POLLARD, HB
联联蛋白（annexin VII）是一种Ca2+和磷脂结合蛋白，已被提出在Ca2+依赖的膜融合过程中发挥作用。利用抗联联蛋白单克隆抗体Mab 10E7和免疫金，我们在牛肾上腺髓质染色质颗粒、静息和尼古丁刺激的肾上腺染色质细胞中进行了联联蛋白的半定量定位研究。分离的染色质颗粒含有很少的联联蛋白，而与联联蛋白（24 μ g/mg）和Ca2+ (1 mM)聚集的染色质颗粒在颗粒膜附近清晰地显示出与联联蛋白相关的免疫金颗粒（每颗粒轮廓1.88金颗粒）。在离体培养的肾上腺染色质细胞中，突触蛋白存在于细胞核（5.5粒/ μ -m2）和细胞质中（5.3粒/ μ -m2），但主要存在于颗粒细胞区颗粒膜周围（11.7粒/ μ -m2）。在胆碱能刺激的儿茶酚胺分泌的活性阶段，突触蛋白标签在细胞核中减少33%，在细胞质中减少23%，在颗粒区域减少51%。质膜中含有少量的联联蛋白，细胞受到刺激后，联联蛋白没有明显变化。我们认为联联蛋白参与了嗜铬细胞的分泌过程。
Synexin (annexin VII) is a Ca2+- and phospholipid-binding protein which has been proposed to play a role in Ca2+-dependent membrane fusion processes. Using a monoclonal antibody against synexin, Mab 10E7, and immunogold, we carried out a semiquantitative localization study of synexin in bovine adrenal medullary chromaffin granules, and in resting and nicotine-stimulated adrenal chromaffin cells. Isolated chromaffin granules contained very little synexin, whereas chromaffin granules aggregated with synexin (24-mu-g/mg) and Ca2+ (1 mM) clearly showed synexin-associated immunogold particles in the vicinity of the granule membrane (1.88 gold particles per granule profile). In isolated, cultured adrenal chromaffin cells, synexin was present in the nucleus (5.5 particles/mu-m2) and in the cytosol (5.3 particles/mu-m2), but mainly around the granule membrane in the granular cell area (11.7 particles/mu-m2). During the active phase of cholinergically stimulated catecholamine secretion, the amount of synexin label was reduced by 33% in the nucleus, by 23% in the cytosol, and by 51% in the granule area. The plasma membrane contained a small amount of synexin, which did not significantly change upon stimulation of the cells. We conclude that synexin is involved in the secretory process in chromaffin cells.